U.S. patent application number 13/416655 was filed with the patent office on 2012-09-20 for oil separator and refrigerating cycle apparatus using the same.
This patent application is currently assigned to SANYO ELECTRIC CO., LTD.. Invention is credited to Susumu Kobayashi, Hiroyuki Satou, Rikio Tadano, Hiroshi Yamawaki.
Application Number | 20120234037 13/416655 |
Document ID | / |
Family ID | 45819010 |
Filed Date | 2012-09-20 |
United States Patent
Application |
20120234037 |
Kind Code |
A1 |
Tadano; Rikio ; et
al. |
September 20, 2012 |
OIL SEPARATOR AND REFRIGERATING CYCLE APPARATUS USING THE SAME
Abstract
An oil separator capable of preventing breakage in a float with
an extremely simple configuration is provided. An oil separator is
to separate oil in a refrigerant that is discharged from a
compressor and return the oil to the compressor. The oil separator
includes: a tank, into which a refrigerant discharged from the
compressor flows; a float having a hollow therein that is held
vertically movably in the tank, the float moving up and down with a
change of an oil level in the tank; and a needle valve to return
oil in the tank to the compressor in accordance with up/down
movement of the float. The float includes an equalizing tube having
a lower end that opens at a bottom part in the float and an upper
end that opens outside of the float and above the oil level in the
tank.
Inventors: |
Tadano; Rikio;
(Maebashi-shi, JP) ; Satou; Hiroyuki;
(Kounosu-shi, JP) ; Kobayashi; Susumu;
(Oizumi-machi, JP) ; Yamawaki; Hiroshi;
(Oizumi-machi, JP) |
Assignee: |
SANYO ELECTRIC CO., LTD.
Osaka
JP
|
Family ID: |
45819010 |
Appl. No.: |
13/416655 |
Filed: |
March 9, 2012 |
Current U.S.
Class: |
62/470 |
Current CPC
Class: |
F25B 43/02 20130101;
F25B 2500/06 20130101; F25B 2700/03 20130101 |
Class at
Publication: |
62/470 |
International
Class: |
F25B 43/02 20060101
F25B043/02 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 16, 2011 |
JP |
2011-057892 |
Claims
1. An oil separator to separate oil in a refrigerant that is
discharged from a compressor and return the oil to the compressor,
comprising: a tank, into which a refrigerant discharged from the
compressor flows; a float having a hollow therein that is held
vertically movably in the tank, the float moving up and down with a
change of an oil level in the tank; and a valve unit to return oil
in the tank to the compressor in accordance with up/down movement
of the float, wherein the float includes equalizing means having
one end that opens at a bottom part in the float and the other end
that opens outside of the float and above the oil level in the
tank.
2. The oil separator according to claim 1, wherein the other end of
the equalizing means opens downward.
3. The oil separator according to claim 1, wherein the other end of
the equalizing means opens obliquely upward.
4. The oil separator according to any one of claims 1 to 3, wherein
the equalizing means is disposed along an outer face of the
float.
5. The oil separator according to any one of claims 1 to 3, wherein
the float includes first and second float members each having a
flange at an end face, the float members being welded at the
flanges, and the equalizing means includes an equalizing path
provided in the flanges.
6. A refrigerating cycle apparatus, comprising a refrigerant
circuit including a compressor, a radiator, a pressure reducing
unit and an evaporator that are connected in a loop, wherein
between the compressor and the radiator is connected the oil
separator according to any one of claims 1 to 3.
Description
TECHNICAL FIELD OF THE INVENTION
[0001] The present invention relates to oil separators to return
oil in a refrigerant that is discharged from a compressor in a
refrigerating cycle apparatus such as a deep freezer and relates to
refrigerating cycle apparatuses using the same.
BACKGROUND OF THE INVENTION
[0002] Conventionally deep freezers used for laboratories or the
like are provided with a refrigerating cycle including a
refrigerant circuit where a compressor, a condenser (radiator), a
pressure reducing unit, an evaporator and the like are connected
sequentially in a loop. This refrigerating cycle is filled with a
refrigerant as well as a predetermined amount of oil to lubricate a
sliding portion of the compressor. A part of this oil is discharged
to the refrigerating cycle from the compressor together with the
refrigerant.
[0003] The oil discharged to the refrigerant cycle hinders
circulation of the refrigerant at the pressure reducing unit and
the evaporator, and causes problems such as burning due to
depletion of the oil in the compressor. To cope with the problem,
an oil separator conventionally is provided between the compressor
and the condenser.
[0004] This oil separator includes a tank with a predetermined
capacity, into which a refrigerant (including oil) discharged from
the compressor flows. Then, the oil in the refrigerant is separated
in the tank with means such as a filter or a centrifugal separator,
and the refrigerant only is made to flow out from the tank to the
condenser. The oil is stored in the tank. A float provided in the
tank floats at the oil level and is vertically movably held in the
tank.
[0005] Accordingly, this float moves up and down with the oil level
in the tank. Then, when the amount of the oil in the tank increases
until the float rises up to a predetermined position with the oil
level, a valve unit opens to let the oil in the tank return to the
intake side of the compressor. Thereby, the oil discharged to the
refrigerating cycle is returned, thus coping with the
aforementioned problem (see Japanese Patent Application Laid-Open
No. H9-72635 (Patent Document), for example).
[0006] Meanwhile, the refrigerant discharged from the compressor is
at an extremely high pressure such as 3 MPa during the operation of
the compressor. On the other hand, when the compressor stops, the
pressure decreases to about 0.5 MPa. Accordingly the pressure in
the oil separator also frequently changes between such a high
pressure and a low pressure. Therefore the float is required to
have strength to withstand such a large pressure change. The float
is typically configured by welding two separated hemispheres
(having a hollow inside) made of metal such as iron or stainless
steel at their flanges, and the welding of high quality is required
as well, thus increasing the manufacturing cost.
[0007] Additionally, due to metal fatigue inevitably generated in
the float because of the pressure change with time, the float may
lose the buoyancy by oil entering into the float through a broken
portion. In that case, the float cannot detect up/down movement of
the oil level and so the oil-returning function is unfortunately
disabled.
[0008] In order to cope with such conventional technical problems,
it is an object of the present invention to provide an oil
separator capable of preventing the breakage of a float with an
extremely simple configuration and a refrigerating cycle apparatus
using the same.
SUMMARY OF THE INVENTION
[0009] An oil separator according to a first aspect of the present
application is to separate oil in a refrigerant that is discharged
from a compressor and return the oil to the compressor. The oil
separator includes: a tank, into which a refrigerant discharged
from the compressor flows; a float having a hollow therein that is
held vertically movably in the tank, the float moving up and down
with a change of an oil level in the tank; and a valve unit to
return oil in the tank to the compressor in accordance with up/down
movement of the float. The float includes equalizing means having
one end that opens at a bottom part in the float and the other end
that opens outside of the float and above the oil level in the
tank.
[0010] According to a second aspect of the present application, the
other end of the equalizing means in the oil separator of the
aforementioned first aspect of the present application opens
downward.
[0011] According to a third aspect of the present application, the
other end of the equalizing means in the oil separator of the
aforementioned first aspect of the present application opens
obliquely upward.
[0012] According to a fourth aspect of the present application, the
equalizing means in the oil separator of the aforementioned aspects
of the present application is disposed along an outer face of the
float.
[0013] According to a fifth aspect of the present application, the
float in the oil separator of the aforementioned first to third
aspects of the present application includes first and second float
members each having a flange at an end face, the float members
being welded at the flanges, and the equalizing means includes an
equalizing path provided in the flanges.
[0014] A refrigerating cycle apparatus according to a sixth aspect
of the present application includes a refrigerant circuit including
a compressor, a radiator, a pressure reducing unit and an
evaporator that are connected in a loop. Between the compressor and
the radiator is connected the oil separator according to any one of
the aforementioned first to fifth aspects of the present
application.
[0015] According to the first aspect of the present application,
the oil separator is to separate oil in a refrigerant that is
discharged from a compressor and return the oil to the compressor,
and the oil separator includes: a tank, into which a refrigerant
discharged from the compressor flows; a float having a hollow
therein that is held vertically movably in the tank, the float
moving up and down with a change of an oil level in the tank; and a
valve unit to return oil in the tank to the compressor in
accordance with up/down movement of the float. The float includes
equalizing means having one end that opens at a bottom part in the
float and the other end that opens outside of the float and above
the oil level in the tank. With this configuration, the space above
the oil level in the tank and the interior of the float can
communicate with each other by the equalizing means.
[0016] This configuration eliminates a pressure difference between
the interior and the exterior of the float. Therefore a problem of
breakage of a float due to a high pressure in the tank and a
pressure change can be solved with a simple configuration even for
a float with a low strength. Accordingly, burning of a compressor
or cooling error of a refrigerating cycle apparatus as in the
aforementioned sixth aspect of the present application can be
effectively prevented while remarkably reducing the manufacturing
cost. In case where oil enters into the float from the other end of
the equalizing means, the oil flows out from the tank through the
equalizing means when the pressure in the tank decreases, and so
this configuration is free from the problem about buoyancy.
[0017] In this case, the other end of the equalizing means opening
downward as in the second aspect of the present application can
effectively prevent or suppress the problem that oil separated from
a refrigerant flowing into the tank and typically dropping from the
filter located above enters from the other end of the equalizing
means.
[0018] The other end of the equalizing means opening obliquely
upward as in the third aspect of the present application allows oil
dropping from the above to tend to flow downward along the outer
face of the equalizing means. Therefore this configuration also can
effectively prevent or suppress entering of oil from the other end
to the equalizing means.
[0019] The equalizing means disposed along an outer face of the
float as in the fourth aspect of the present application can
eliminate the necessity of providing equalizing means in the float,
thus improving productivity more.
[0020] As in the fifth aspect of the present application, the float
includes first and second float members each having a flange at an
end face, the float members being welded at the flanges, and the
equalizing means includes an equalizing path provided in the
flanges. This configuration can realize equalizing means without
using a pipe or the like, thus reducing the number of components
and leading to the improvement of productivity.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is a refrigerant circuit diagram of a deep freezer
that is an embodiment of a refrigerating cycle apparatus to which
the present invention is applied.
[0022] FIG. 2 is a vertical sectional view of an oil separator of
the present invention.
[0023] FIG. 3 is another vertical sectional view of an oil
separator of the present invention.
[0024] FIG. 4 illustrates the state where the float of the oil
separator of FIG. 2 moves up.
[0025] FIG. 5 illustrates another embodiment of a float of an oil
separator of the present invention.
[0026] FIG. 6 illustrates still another embodiment of a float of an
oil separator of the present invention.
[0027] FIG. 7 illustrates a further embodiment of a float of an oil
separator of the present invention.
[0028] FIG. 8 illustrates a still further embodiment of a float of
an oil separator of the present invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0029] The following describes embodiments of the present invention
in detail, with reference to the drawings. A refrigerant circuit
illustrated in FIG. 1 is to cool the chamber (not illustrated) of a
deep freezer 1 that is an embodiment of a refrigerating cycle
apparatus of the present invention to ultracold temperatures from
-80.degree. C. to -150.degree. C., and the refrigerant circuit
includes a high-temperature side refrigerant circuit 2 and a
low-temperature side refrigerant circuit 3 cascaded to the
high-temperature side refrigerant circuit 2.
[0030] The high-temperature side refrigerant circuit 2 includes: a
compressor 4; a condenser 6 as a radiator; a capillary tube (or an
expansion valve) 7 as a pressure reducing unit and an evaporator 8
that are connected sequentially in a loop via pipes. The
low-temperature side refrigerant circuit 3 includes: a compressor
9; an oil separator 11 according to the present invention; a
condenser 12 as a radiator; a capillary tube (or an expansion
valve) 13 as a pressure reducing unit and an evaporator 14 that are
connected sequentially in a loop via pipes. The condenser 12 of
this low-temperature side refrigerant circuit 3 and the evaporator
8 of the high-temperature side refrigerant circuit 2 are arranged
in a heat-exchange relationship, thus configuring a cascade heat
exchanger 16.
[0031] The detailed configuration of the oil separator 11 is
described later. The oil separator 11 plays a role to separate oil
in a refrigerant discharged from the compressor 9 of the
low-temperature side refrigerant circuit 3 and return the oil to
the compressor 9, where a discharge pipe 9D of the compressor 9 of
the low-temperature side refrigerant circuit 3 is connected to a
refrigerant inlet pipe 17 of the oil separator 11 and a refrigerant
outlet pipe 18 of the oil separator 11 is connected to the
condenser 12. An oil returning pipe 19 of the oil separator 11 is
connected to a suction pipe 9S of the compressor 9.
[0032] Then, when the compressor 4 of the high-temperature side
refrigerant circuit 2 is operated, gas refrigerant at a high
temperature and a high pressure discharged from the compressor 4
flows into the condenser 6, and dissipates heat there to condense
into liquid. The refrigerant subjected to condensation at the
condenser 6 then is squeezed by the capillary tube 7 and then flows
into the evaporator 8 for evaporation. At this time, the
refrigerant exerts an endothermic effect. The refrigerant
evaporated at the evaporator 8 is sucked into the compressor 4
again for repeated circulation.
[0033] When the compressor 9 of the low-temperature side
refrigerant circuit 3 is operated, gas refrigerant at a high
temperature and a high pressure discharged from the discharge pipe
9D of the compressor 9 flows into the oil separator 11 through the
refrigerant inlet pipe 17. Refrigerant gas from which oil has been
separated by this oil separator 11 flows out from the refrigerant
outlet pipe 18, and flows into the condenser 12. Herein, the oil
separated by the oil separator 11 is returned to the suction pipe
9S of the compressor 9 via the oil returning pipe 19 as described
later.
[0034] In order to achieve the aforementioned ultracold
temperatures, the low-temperature side refrigerant circuit 3
contains a refrigerant with an extremely low boiling point therein.
The refrigerant, however, can condense into liquid smoothly because
the condenser 12 is cooled by the endothermic effect by the
evaporator 8 of the high-temperature side refrigerant circuit 2 at
the cascade heat exchanger 16. The refrigerant subjected to
condensation at the condenser 12 then is squeezed by the capillary
tube 13 and then flows into the evaporator 14 for evaporation. At
this time, the refrigerant exerts an endothermic effect to cool the
chamber not illustrated. Then the compressor 9 is turned ON and OFF
in accordance with temperatures in the chamber, so that the chamber
is cooled to set temperatures in the ultracold temperature range
from -80.degree. C. to -150.degree. C. as described above.
[0035] The refrigerant evaporated at the evaporator 14 is sucked
into the compressor 9 again through the suction pipe 9S for
repeated circulation. At this time, the oil flowing back through
the oil returning pipe 19 as well as the refrigerant from the
evaporator 14 are returned to the compressor 9 via the suction pipe
9S.
[0036] The following describes one embodiment of the oil separator
11 of the present invention, with reference to FIG. 2 to FIG. 4. In
these drawings, reference numeral 21 denotes a tank with a
predetermined capacity having a vertically long cylindrical shape.
The tank 21 is hermetically sealed above and below so as to
withstand high pressures. The refrigerant inlet pipe 17 and the
refrigerant outlet pipe 18 are inserted into this tank 21 from the
above and open at an upper part in the tank 21. The oil returning
pipe 19 also is inserted into the tank 21 from the above and opens
at a bottom part in the tank 21.
[0037] Around the opening of the refrigerant inlet pipe 17 in the
tank 21 is attached a filter 22, and the filter 22 separates oil in
the refrigerant gas flowing from the refrigerant inlet pipe 17 as
stated above. The separated oil drops from the filter 22 and is
stored in the bottom part of the tank 21. The refrigerant gas from
which oil has been separated by the filter 22 flows into the
refrigerant outlet pipe 18 via the interior of the tank 21, and
flows out to the condenser 12 from the oil separator 11. This
prevents the oil from flowing out to a downstream of the oil
separator 11 of the low-temperature side refrigerant circuit 3, and
can avoid problems such as a failure in refrigerant circulation due
to solidification of the oil at a portion at ultracold temperatures
such as at the evaporator 14 as state above. The refrigerant inlet
pipe 17 and the refrigerant outlet pipe 18 in the tank 21 are
separated by a partition 23 to prevent a so-called short circuit of
the refrigerant gas.
[0038] At the lower part of the tank 21 is housed a float 24 having
a hollow therein. This float 24 floats at the oil level of the oil
separated by the filter 22 and stored in the bottom part to play a
role of detecting the oil level. The float 24 is held vertically
movably to the oil returning pipe 19 via a float lever 26 and a
mounting hardware 27.
[0039] That is, the mounting hardware 27 is attached at a lower end
portion of the oil returning pipe 19, and one end portion of the
float lever 26 is vertically rotatably and pivotably supported by
this mounting hardware 27 around a revolution shaft 28 in the
horizontal direction. Then, the other end of the float lever 26 is
welded for fixing to a side face of the float 24, thus allowing the
float 24 to be held vertically movably in the tank 21 below the
filter 22 or the like. The one end of the float lever 26 further
extends from the revolution shaft 28 in the direction opposite to
the float 24, and to this extension 26A is rotatably attached a
lower end of a needle valve 29 (valve unit). The upper end of this
needle valve 29 corresponds to the position of the lower end
opening of the oil returning pipe 19. When the needle valve 29
moves up, the upper end thereof blocks the lower end opening of the
oil returning pipe 19 and when the needle valve 29 moves down, it
opens the lower end opening. Reference numeral 31 denotes a holder
to hold the positions of the oil returning pipe 19 and the float 24
in the tank 21.
[0040] As described above, oil separated from the refrigerant gas
by the filter 22 drops from the filter 22 and is stored in the
bottom part of the tank 21. The float 24 floats at the oil level of
the stored oil. When the amount of the oil increases, the oil level
rises and accordingly the float 24 also rises. Therefore, the float
lever 26 rotates clockwise in FIG. 2 around the revolution shaft 28
and assumes the state of FIG. 4. This rotation rotates the
extension 26A as well clockwise, and therefore the needle valve 29
is pulled up, thus letting the lower end opening of the oil
returning pipe 19 open (FIG. 4). As a result, since the interior of
the tank 21 is at a high pressure during the operation of the
compressor 9, the oil stored in the tank 21 flows into the lower
end opening of the oil returning pipe 19 and is returned to the
compressor 9 via the oil returning pipe 19 as stated above. This
can prevent burning of the compressor 9 due to depletion of the
oil.
[0041] When the oil flows out, the amount of the oil in the tank 21
decreases and accordingly the oil level drops. Then, the float 24
also descends, and therefore the float lever 26 rotates
counterclockwise in FIG. 2 around the revolution shaft 28. This
rotation rotates the extension 26A as well counterclockwise, and
therefore the needle valve 29 is pushed upward, thus blocking the
lower end opening of the oil returning pipe 19 (FIGS. 2 and 3).
This can adjust the oil amount in the tank 21 of the oil separator
11 always not to exceed a predetermined value.
[0042] The following describes the configuration of the float 24 in
the oil separator 11 of the present invention. All of the floats 24
in the following embodiments are spheres having a hollow therein,
including two separated hemispherical (having a hollow inside)
first and second float members 24A and 24B made of stainless steel
with flanges, which are mutually welded at the flanges F around the
openings for fixing. As illustrated in FIG. 2 and FIG. 3, the
second float member 24B that is the uppermost part of the float 24
in the state where the float 24 descends has a hole bored therein,
through which an equalizer tube 32 made of a thin copper pipe
making up equalizer means of the present invention is inserted.
[0043] A lower end 32A (one end) of this equalizer tube 32 opens at
a bottom part in the float 24. In this embodiment, an upper end 32B
(the other end) of the equalizer tube 32 sticks out from the float
24 and then is bent downward, and opens downward above the oil
level of the oil in the tank 21. Herein, a gap between the
equalizer tube 32 and the hole of the second float member 24B is
sealed by welding.
[0044] As described above, during the operation of the compressor
9, since gas refrigerant at a high temperature and a high pressure
is discharged from the compressor 9 and flows into the oil
separator 11, the pressure in the tank 21 increases up to about 3
MPa in this embodiment. When the compressor 9 stops, the pressure
in the tank 21 decreases to about 0.5 MPa. Conventionally the float
members 24A and 24B configuring the float 24 and the welding
portion of the flanges F are required to have a strength to
withstand such a high pressure and to avoid metal fatigue due to
such a pressure difference. This is because, if the float 24 breaks
and oil enters into the float 24, the float will lose the buoyancy,
which means that the needle valve 29 is kept close and oil cannot
be returned to the compressor 9.
[0045] According to the present invention, however, the equalizer
tube 32 allows the interior of the float 24 and the space above the
oil level of the oil in the tank 21 to communicate with each other,
thus eliminating the pressure difference between the interior and
the exterior of the float 24 (pressure is equalized). As a result,
the float 24 does not break without such a pressure-withstanding
strength and welding quality. Accordingly, although the float in
the present embodiment is made of stainless steel, the float 24 may
be shaped with other metals or materials other than metal such as
hard synthetic resin. Therefore, burning of the compressor 9 or
cooling error of the deep freezer 1 can be effectively prevented
while remarkably reducing the manufacturing cost.
[0046] Note here that the attachment of the equalizer tube 32
increases the weight of the float 24 itself, and therefore a
material and dimensions of the equalizer tube 32 have to be decided
with consideration given to margin of the buoyancy of the float 24.
This margin of the buoyancy is decided by balance among the maximum
buoyancy of the float 24 itself, the buoyancy of the float 24
around the revolution shaft 28 of the float lever 26 and moment of
an application force of the needle valve 29, and therefore the
material and the dimensions of the equalizer tube 32 are set so
that the buoyancy can be within such margin even after the
attachment of the equalizer tube 32.
[0047] In this embodiment, the float 24 is made of stainless steel,
and has the volume of 137.3 (cc), the weight of 71.4 (g), the
surface area of 128.7 (cm.sup.2) and the maximum buoyancy of about
52.1 (g). Then, the margin of the buoyancy on the basis of the
balance with the float lever 26 is about 17.9 (g). Then, when the
equalizer tube 32 is made of a copper pipe as in the embodiment,
the weight thereof is about 2.0 to 5.3 (g) even when the outer
diameter is 2.4 to 4.76 (mm), the inner diameter is 1.2 to 3.46
(mm), the material thickness is 0.4 to 0.65 (mm) and the length is
70 (mm). Accordingly, enough buoyancy can be obtained. The same
should apply to the case of using a stainless steel pipe or an iron
pipe having a smaller specific gravity than a copper pipe.
[0048] Further, since the other end 32B of the equalizer tube 32
opens downward in this embodiment, oil dropping from the filter 22
located above hardly enters into the float 24 from the other end
32B of the equalizer tube 32. In case where oil enters into the
float 24 from the other end 32B of the equalizer tube 32, when the
compressor 9 stops and the pressure in the tank 21 decreases, oil
at the bottom part in the float 24 flows from the lower end 32A of
the equalizer tube 32 to the equalizer tube 32 and passes
therethrough to flow out from the upper end 32B to the tank 21 as
stated above. Therefore, this configuration is free from the
problem of buoyancy due to the flowing oil.
[0049] However, in order to suck up oil in the float 24 with the
equalizer tube 32 when the pressure in the tank 21 decreases, the
equalizer tube 32 has to be filled with oil when the oil enters
into the equalizer tube 32 from the lower end 32A. Although this
sucking-up action is influenced by the viscosity of oil, when the
inner diameter of the equalizer tube 32 is too large, oil cannot be
sucked up from the float 24 when the pressure in the tank 21
decreases.
[0050] Conversely when the equalizer tube 32 is too thin, the
equalizer tube 32 may be collapsed during welding to the float
member 24B. Therefore, the outer diameter and the inner diameter of
the equalizer tube 32 have to be selected with consideration given
to these matters. In the embodiments, a copper pipe having the
outer diameter of 3 (mm), the inner diameter of 2.2 (mm) and the
material thickness of 0.4 (mm) was used, and it was confirmed by an
experiment that the equalizer tube 32 had sufficient sucking-up
ability when the pressure in the tank 21 decreases.
[0051] FIG. 5 is a cross-sectional view of a float 24 in another
embodiment of the present invention. In this case, an equalizer
tube 32 includes a straight pipe, and an upper end 32B thereof is
directed upward in the tank 21. Even such an equalizer tube 32 can
eliminate a pressure difference between the interior and the
exterior of the float 24. However, the upper end 32B directed
downward as in the aforementioned embodiment can effectively
prevent or suppress the problem that oil separated from a
refrigerant flowing into the tank 21 and dropping from the filter
22 located above enters from the other end 32B of the equalizer
tube 32.
[0052] FIG. 6 is a cross-sectional view of a float 24 in still
another embodiment of the present invention. In this case, the
other end 32B of the equalizer tube 32 opens to be directed
obliquely upward. Such a configuration allows oil dropping from the
above to tend to flow downward along the outer face of the
equalizer tube 32 obliquely descending from the other end 32B, thus
suppressing the oil from flowing into the equalizer tube 32 from
the opening of the other end 32B, and therefore entering of the oil
to the equalizer tube 32 can be effectively prevented or
suppressed.
[0053] FIG. 7 is a cross-sectional view of a float 24 in a further
embodiment of the present invention. In this case, the equalizer
tube 32 has a curved shape along the outer face of the float 24 and
is welded for fixing to the outer face. Then, a lower end 32A
thereof is inserted through a hole formed at a lower end portion of
the float 24 and opens at a bottom part of the float 24. Then,
similarly to the aforementioned embodiment, an upper end 32B opens
downward above the float 24.
[0054] The equalizer tube 32 provided along the outer face of the
float 24 in this way can eliminate the necessity to insert the
equalizer tube 32 in the float 24 as in FIG. 2, FIG. 5 and FIG. 6,
and therefore productivity can be more improved.
[0055] FIG. 8 is a cross-sectional view of a float 24 in a still
further embodiment of the present invention. In this case, first
and second float members 24A and 24B configuring the float 24
include grooves formed at flanges F thereof beforehand so as to be
opposed mutually, and in these grooves an equalizing path
(equalizing means) 33 is formed. A lower end 33A of the equalizing
path 33 opens to the interior of the float 24 at a bottom portion
of the float 24, and an upper end 33B of the equalizing path 33
opens externally at an upper portion of the float 24.
[0056] When forming this equalizing path 33, the flanges F at a
portion other than the part corresponding to the equalizing path
are mutually bonded firstly, and pressure is applied thereto to let
a not-bonded portion swell. Thereby the aforementioned opposed
grooves are formed at the flanges F of both of the float members
24A and 24B, and the interior therebetween becomes the equalizing
path 33. The thus formed equalizing path 33 in the flanges F can
eliminate the necessity of attaching a pipe, thus reducing the
number of components and leading to the improvement of
productivity.
[0057] In these embodiments, the present invention has been
described by way of the oil separator 11 that mechanically controls
the returning of oil by the vertical movement of the float 24 using
the float lever 26 and the needle valve 29. The present invention,
however, is not limited to such an example, and is also effective
to an oil separator as in the aforementioned Patent Document 1
where the vertical movement of a float 24 opens and closes a
contact and so opens and closes an electromagnetic valve (valve
unit) provided at an oil returning pipe 19.
* * * * *